Small block ford engine mounts

pszlamas · May 02, 2010, 09:17:29 PM

Hi all, my name is Pete and first I'd like to say what an excellent resource this site has been to me!

I recently purchased a 1976 mgb roadster with hopes of converting it to V8 power. Its a near rust free california car that was in the process of restoration but the PO ran out of funds. I have a 351 that I had built a few years ago for a project that I lost interest on. The motor is pretty well built, aftermarket heads, matching cam and all the other bells and whistles. It was a nasty motor in my previous project car approx 450hp. My plan is to swap the 351 in with either a t5 or toploader four speed. I'm a welder by trade and I do posses alot of fabrication skills. Although I dont have alot of time to work on my toys, I like to make a plan and follow the best I can. For right now I want to get by with notching and using the stock crossmember and rebuild the front suspension with urethane bushings and maybe a tube shock conversion. I'd like to use the the stock mgb rear end for a year or so then narrow and old 8.8 ford i have.

I've been searching the forums and lurking for a while. I see how many members have swapped 302's in and I would go the same route but I still have the 351 that I need to do something with. I do know that 302's and 351's share the same motor mounts, bell housing and some other bits. The 351 has a taller deck and provided that all else are the same the 351 should drop in with some firewall and hood modifications which I am not afraid to do. Headers will be about the biggest challenge for me only because I dont have a tube bender so I will have to use a box of j and u bends and cut alot.

My first question is concerning the motor mounts, I see 64 comet/falcon motor mounts are popular, but all I can find are the motor mount pads and not the frame side mounts. Where should I get these at? if need be I can make them myself but If i can purchase them for a good price I will in the interest of saving time.

Second is concerning the transmission choice. I'm leaning towards a top loader 4 speed but i'm concerned with the external shift linkage. The tunnel is pretty narrow and I like to not cut it all up. Are the benefits of a 5 speed really that great over a 4 speed. I'd like to drive the car wherever and still have a few creature comforts. I'm not sure what rpms I would be turning with the OD compared to not having any.

Thanks in advance for all the help, I will be posting pictures of progress as I go.

pspeaks · May 03, 2010, 03:51:28 AM

Pete, first welcome to the group; there are any number of guys on this site who know more about what's ahead of you than I, but I just did it and offer what little I know and my opinion for what it's worth. First, the rule is sooner or later you're going to have to disengage the clutch. An internal hydraulic throw-out bearing works well until it leaks and you have to disassemble the whole car to fix it. The alternative is cable which nobody seems to use or an external slave cylinder and mount which takes up pretty much all available room for shift linkage. I've had both four and five speed set ups and I think you'll wish you had that extra gear, and the OD really comes in handy. I have a 72 which is a little more difficult than a 76 but count on more time to rebuild the firewall than you think, it can be a pain making templates and cutting sheet metal, plus there is a lot of grinding afterwards. All that said, I would do it again in a minute. No one has commented on my motor mounts ( see carb to hood clearance on this site) I guess nobody likes them, but you won't believe the room I have for steering and exhaust. "P"

pszlamas · May 03, 2010, 10:49:46 AM

Hey Paul, thanks for the advice. I've looked at your thread before and never even noticed those motor mounts. They look great. I've seen those in a few parts places that carry those for 302's but never a 351 but I would imagine they cant be too difficult to make.

As for the clutch, I've experienced the pain of hydraulic throwout bearings before. I have a 77 f-150 I converted to a mazda 5 speed which uses a internal slave. I dont think I'll ever use one again. I would rather use a small push type external slave on the bellhousing for the 4 speed to save room. I plan to make RV8 style headers and dump them out the side. Finding a decent t5 around here is getting difficult. Most are trashed and still aking $500. I can get a rebuilt top loader for that. With the low wieght of the car and the power of my motor I think if I had a rear gear of around 3.08 or even higher like 2.73 it would cruise well in 4th gear and still pack quite a punch running from 1st to 4th. I fear traction will be an issue still but will be even worse with 3.55's or lower.

mgb260 · May 03, 2010, 11:22:24 AM

The original MGB frame mounts are cut off and saved. Notch and patch footboxes to heater shelf for clearance. Notch and weld crossmember.I grind those little tabs off the block too.The early "Comet,Fairlane,Mustang,Falcon" rubber mounts are bolted to the block and the block is put in place. The steering rack fits between the damper and oil pan. The original MGB frame mounts are bolted to the "Comet" mounts and tacked into place. Remove the block and weld solid.

pszlamas · May 03, 2010, 05:44:41 PM

Exactly what I was trying to find! I found the mounts at autozone for 26 bones, I hate the zone but for once they had what I needed and will be here tomorrow morning. Summit racing doesnt carry the polyurethane mounts but the duracrap ones should work well for now. I'm glad I cut the mounts out clean this morning before I read you post jim lol. I'm borrowing a small plasma cutter tomorrow, I hope that will save alot of time notching the crossmember and cutting back the firewall so hopefully I can at least get the motor tacked and test fit tomorrow so I can fit and finish the firewall and floor pans.

mgb260 · May 03, 2010, 06:43:48 PM

I don't know why more people don't use the 351W. About a 1 1/2" taller and wider. Strokers up to 427.The 94-97 (5.8 truck) is roller cammed. You could use a Chevy type cowl induction or Cobra scoop. The LS motor is about the same size but,must be a little lower if you can use a stock hood though.

pspeaks · May 03, 2010, 07:03:56 PM

I followed tradition and used a CNC push slave cylinder from Speedway and modified the shortened throwout arm to accept a 3/8" rod end (shaft not built at the time, but I've learned not to try to measure thin air). We built the motor mounts and transmission crossmember from scratch, but I have access to a complete machine shop and a lot of talented friends. Keep us up to date, we love to see how others overcome the beast. "P"

ex-tyke · May 03, 2010, 09:30:01 PM

QuoteI don't know why more people don't use the 351W. About a 1 1/2" taller and wider. Strokers up to 427.The 94-97 (5.8 truck) is roller cam....

One reason is that anything above 300 hp is really a waste since it becomes difficult to get that power to the ground.
My 302 has about 250rwhp and 225 wide rubber and wheel spin comes on very easily.

pspeaks · May 03, 2010, 10:02:47 PM

When it comes to wheel spin my bucket is fearsome, and sometimes hard to control, but thats OK because that's what it was built for. The MG is only pushing about 230 HP and I'll bet wheel spin will be a problem for me there as well. My plan is to try to be a little more mature and frugal with the MG, well, within the limits of my personality that is.

MGBV8 · May 04, 2010, 10:01:35 PM

"An internal hydraulic throw-out bearing works well until it leaks and you have to disassemble the whole car to fix it."

Sorry, Paul, but I've never really bought into this argument. Whatever did we all do when the carbon release bearing died an early death on a stock MG?

Second thing is that on many of these conversions (including mine), the tranny can be pulled while leaving the engine in place. That means pull the trans & the clutch, HTOB, flywheel, bellhousing all can be serviced with the engine in place.

Even with the external slave cylinder you still have to worry about that release bearing.

pspeaks · May 05, 2010, 01:22:23 AM

Good, remember Carl, I said it is just my opinion and there are people here who know much more than I, and well I guess you're one of them. Thanks for setting me straight, however, I still have no intention of using a HTOB and think the real possibility of a hydraulic leak on the clutch is not good. Admittedly a number of people use them without a problem, but people on this site have had and complained about leaks and nobody can tell me it's easier to fix a leak inside the bell housing than on the side of the transmission, but as I always say, Do what you want, I do.

pszlamas · May 12, 2010, 05:12:21 PM

Well I made the motor mounts the other day and have them welded in. I found a t5 that is supposedly rebuilt and will be mounting that and fabbing the crossmember later. I still have to weld the crossmember up and finish the floors and patch the firewall. Next big hurdle will be making headers. There is plenty of room for them fortunetly. I had to mount the motor a bit higher than I wanted to to keep from totally interfering with the steering shaft and column. Other than that it fits rather nicely. Hood clearance is the only issue I see but thats ok for me at this time.

mgb260 · May 12, 2010, 06:13:33 PM

Pictures Pete? I always wanted to do this! Just having a little fun.

pspeaks · May 13, 2010, 12:17:57 AM

Pete, I'm a fair fabricator, but certainly no "Tin-Man." I had a lot of trouble with the fire wall and all my friends kept saying "tac-tac-tac." I made templates out of cheap matte-board and taped them together to mock up the fire wall. After transferring them to metal, and a little bending with a brake, I was able to reduce the number of welded seams; I hate grinding. I still plan on using Pete Mantell's headers, but keep us posted and Jim is right, post some pictures.

302GT · May 17, 2010, 07:44:11 PM

I used a push slave cylinder that pushes on the dimple in the clutch fork where the cable normally mounts. The clutch fork is hardened and has shown no signs of wear in 40,000 miles. I had to shorten the push-rod, and it wears a litte such that clutch adjustment is needed about every 10,000 miles (but this is easy). I made a simple bracket to hold the slave cylinder to ribs on the T-5 transmission case.

pszlamas · October 17, 2010, 06:52:33 PM

Hello again!

Well things have dropped off since the summer. I have been working in Wyoming since august and being away from the car has given me lots of time to rethink my swap. I have since found a nicer car to start with. I picked up a 71 B chrome bumper that has been 90% restored but the motor was trash. Fresh yellow paint, new tan interior and all body parts including a useable top Rebuilt and painted suspension and underbody. Fortunetly I picked it up for a song, which the car is miles ahead of the 76 I have now. What I paid for the car is much less than purchasing a full interior kit.

With this new car I want to focus more on keeping the car comfortable, appealing, and reliable. My original plan was to have a stripped down race ready rod, no heat, spartan interior ect... I have built rods like that before and none of them I enjoyed driving more than 15 mins and I never raced. I will be purchasing a plastic mock block to aid in placing the motor. I usually work by myself so not having to use a hoist will help. I want to cut as little as possible on this car and in the footbox area. My previous placement in the 76 caused me to get a little judicious with the plasma cutter lol. Not having a brake makes that alot of patch work.

Unfortunetly I am not happy with the engine mounting solution I came up with before. I had to cut and weld on the comet mounts I got from autozone to get them to clear the frame and steering. I am concerned with the mounts being rubber that they are trashed after being hot from welding and grinding. Although I blew 26 dollars for mounts I'm not concerned. There I learned this might be more difficult than I expected.

I have searched and looked through nearly every ford swap and how it was done articles and I still am not clear on a solution. Does anyone have photographs of different mounting solutions inluding the comet mounts or even better part numbers?

pspeaks · October 17, 2010, 08:35:38 PM

Pete,

Obviously there are different solutions but this is the one I choose because it solved my motor mount/steering shaft conflict, but I'm sure there are others that do that too. Also I have access to a CNC machine which made it easy for me to cut them out and TIG the pieces together. Be advised a chrome bumper car is different under the hood than a rubber bumper. Develop a plan before you start and remember it's easier to remove just a little bit more than it is to put metal back in. Of course if I had been a better Tin Man it would have gone better for me; I'm just not very good at it.

pspeaks · October 17, 2010, 08:42:18 PM

I forgot to mention we have used this on various street rods in the past and I was concerned about having the mounts attached to the heads but so far we haven't had an issue with it. Also I had a friend who used a plasma cutter; my recommendations for what ever they are worth, mark exactually where you want to cut (I use a gray sharpie because it's easier to see) and use a cut-off wheel whenever possible: a much cleaner edge to work with.

"P"

302GT · October 21, 2010, 07:24:56 PM

I used Chaterham 7 mounts. They attach to flat plates on the block and to flat plates off of the chassis rails or the crossmember (better to use the cross member). It is important to add braces to the chassis/crossmember mounting plates.

MGB SS · October 21, 2010, 08:15:14 PM

Pete

Like Paul I built my motor mounts off of the head making all kinds of room for steering and exhaust if you go through there.

I have had zero issues with this set up and wouldn't hesitate to build them again.

As mentioned above the Chrome Bumper Car has less clearance in the trans tunnel and fire wall area than the 76= More Cutting.

On the subject of Slave cylinder I went with a close mounted external type actually going through the back of the bell housing not next to it

pspeaks · October 22, 2010, 08:52:01 AM

Joe, I like your slave cylinder installation and think your throwout rod stays strighter in it travel, but by the time I saw it I had already modified my throwout arm and built a transmission side mount bracket. It was a pretty tight fit compared to yours. If I ever have to do it again I think I'll copy your idea, but I'll tell everybody it your idea. "P"

pszlamas · October 22, 2010, 08:26:04 PM

like those mounts Paul, I shyed away from using them because I felt the comet mounts would be easier. Unfortunetly The mounts cross up on the steering shaft. What are you using on those mounts? Looks like 3/16 or 1/4" plate. The hardest part for me would be getting the bolt pattern of the heads transfered in the right location as to mount the motor square. Did you use any special technique to achieve that? Also are those just generic rubber pads seen in any parts catalog? What do you have planned for mounting the alt? I would think replacing one or two bolts with studs and securing the plate with nuts would work fine. Albeit the 351 is a tad taller and wider but I can make something like that.

Yea I kind of learned the hard way to use the plasma sparingly. I dont work with sheetmetal or anything thinner than 3/16 material much at all within the past couple years. Most of my fitting and fabrication skills come with working on big iron, tubes/pipe ect.... We use plasmas and torches quite a bit but it really leaves a rough edge on sheet metal to work with, which leaves it difficult to grind a straight line in it. I'll be sure to use the right tools for the job this time. ie cutoff wheels, body saws and snips. On the welding side, thats where I feel most comfortable. I cut my teeth in welding using tig and mig on thin material. So as long as I can cut and fit my patches in nice the rest is a breeze.

I've ordered the plastic block and some other parts. And my pop should be picking up the new car this weekend. Maybe I can get some pictures of it. Hopefully when I get back to ohio I can get some work done. Thanks again!

BlownMGB-V8 · October 23, 2010, 10:30:34 AM

Take a look at the mounts on the MG-Roadmaster thread and on the 340 thread. The latter ones were the second take and came out much nicer, using about 7 ga stainless. Typically a cardboard template is used and then holes are transferred using transfer punches screwed into the bosses. These are easy to make by cutting off a short piece from an allen wrench, loctite that into a setscrew, and grind the end pointy. Then a small socket is used to screw it in and out. Cushions are from the McMasterCarr catalog.

JB

pspeaks · October 23, 2010, 11:08:17 AM

They were cut out of 3/16" and reinforced and stiffened around the edges with 1/8" X 1/2", cold roll if you can because I think it looks and paints better. I let by shop mate Richard put it in the computer and the CNC machine cut it out then I TIG'ed the ½" stuff and the foot the rubber goes through which I think was 3/8 but I'm not sure; I'll measure it later today when I get to the hanger and post it here. Get your motor exactly where it's going to be and make mat-board (because it's stiffer) templates. Even though I used a computer and a CAD program to drive the CNC, I'm a big believer in templates and jigs which I used to locate the bolt holes on the head and you can cut them for very little money until you get what you like then do metal. Also remember the two sides are not the same length because one head is further forward than the other and the frame slopes up. I also used mat-board templates when putting the firewall back together.

The rubber mounts are from McMaster (6309K37), about $5.95 ea. side, and can be ordered over the internet. Though I've never done it, I think Bolt through rubber mounts, as used on roadsters, can be ordered from Speedway as well. This is getting long so I'll show you how I did the alternator in another post. I hope this helps.

I didn't include any dimensions as these things are mostly hand built and very often measurements don't translate from one car to another.

"P"

pspeaks · October 23, 2010, 11:21:44 AM

I used a GM 3-wire alternator a friend gave me and let the computer cut out the bracket for me. For the adjuster rod I used a 5/8" aluminum rod and through drilled it on a lathe then threaded one end with 5/16" right hand threads and the other with left hand threads. I know it looks a little silly but the bungee card is to give me a little visual reference, it still has to be shimmed to make the belt run straight.